Transmitters with Multi-Tag Paths

Prerequisites:

• Knowledge of Ignition and Module installation process: Cirrus Link Module Installation
• Install the following MQTT Modules
  
  • MQTT Distributor
  • MQTT Transmission

Overview:

MQTT Transmission allows for a multi-tag path to be defined for a Transmitter. This can be useful for when you have tags across multiple Edge Gateway tag providers that so they can be consumed by a single Transmitter and therefore contained within a single Edge Node and/or device by MQTT Engine rather than split across two different edge nodes.

It will be helpful to have reviewed and understood the MQTT Transmission Transmitters and Tag Trees which describes how MQTT Transmission Transmitter configurations interact with Ignition tag trees to publish MQTT messages and tags to an MQTT Server. 

There are some basic rules to the multi-tag path configuration:

• Tag Provider and Tag Path are used in combination to define that start of the tag tree to use
  
  
• Specific Tag Providers can be specified in the Tag Path using the format [TagProvider]
  
  • If the Tag Provider is not explicitly defined in the Tag Path, Transmission will use the Tag Provider property
  • If the Tag Provider is explicitly defined in the Tag Path, Transmission will use the [TagProvider] configured

• Multiple tag paths should be comma separated in the Tag Path property for each Transmitter

Let's put some examples together showing how the multi-tag path feature works.

Following the Ignition Tag Provider Guide, configure two new Realtime Tag Providers as type Standard Tag Provider to the Ignition instance naming them TagProvider1 and TagProvider2. 

In Ignition Designer, create a tag tree under each Tag Provider as shown below: 

Let's create a transmitter using these properties and use MQTT Transmission refresh mechanism to publish the tags

At MQTT Engine, we will see the following three tag trees each starting at one of the three Tag Paths specified:

• Edge Nodes
• TagProvider1
• TagProvider2

Let's create a second transmitter using these properties and use MQTT Transmission refresh mechanism to publish the tags

At MQTT Engine, we will see two additional tag trees created each starting at one of the two Tag Paths specified

• TagProvider1/A1
• TagProvider2/L1

Let's create a third transmitter using these properties and use MQTT Transmission refresh mechanism to publish the tags

At MQTT Engine, we will see two additional two tag trees created each starting at one of the Tag Paths specified

• TagProvider1/A1/B1/C1
• TagProvider2/L1/M1/N1

Finally lets add a fourth transmitter using the same configuration as one of our other examples but setting the Group ID under the Sparkplug IDs to prevent any colliding Edge Node IDs. 

At MQTT Engine, we will only ONE additional tag tree with a parent folder named "MyGroup" but containing child folders for each Tag Path specified

• TagProvider1/A1
• TagProvider2/L1